Developing apparatus for photographic film,particularly x-ray film



May 13; 1969 A 5 HQLM AL 3,443,503

DEVELOPING APPARATUS FOR PHOTOGRAPHIC FILM, PARTICULARLY I X-RAY FILM Filed Jan. 17, 1966 I Sheet of 2 4 2 11 3.3 1e .34" W I 6 9 6 May 13, 1969 5, HQLM ETAL 3,443,503

' DEVELOPING APPARATUS FOR PHOTOGRA'PHIC FILM, PARTICULARLY X-RAY FILM Filed Jan. 17, 1 966 Sheet 1 r 2 United States Patent 3,443,503 DEVELOPING APPARATUS FOR PHOTOGRAPHIC FILM, PARTICULARLY X-RAY FILM Sune Erik Holm, Vallingby, and Lars Torsten Jevbratt,

Vaxholm, Sweden, assignors to Jarnhs Elektriska Aktiebolag, Solna, Sweden, a corporation of the Kingdom of Sweden Filed Jan. 17, 1966, Ser. No. 527,640 Claims priority, application Sweden, June 11, 1965, 7,679/65; Oct. 14, 1965, 13,303/65 Int. Cl. G03d 3/10 U.S. CI. 9589 5 Claims ABSTRACT OF THE DISCLOSURE Photographic developing apparatus having a series of liquid processing baths. A rotating shaft having a film hanger device is provided for transporting film successively through the baths. A camming device cooperates with the hanger to raise and lower the film into the baths.

The present invention relates to developing apparatus for photographic film, particularly X-ray film, said apparatus being provided with hangers for the film, said hangers being arranged to be propelled along a series of consecutive processing baths and, in the course of the processing, to dip the film successively in the consecutive processing baths.

In prior art developing apparatus of this kind are known in which a rod carrying the film to be processed is displaced parallel to itself above the various processing baths by means of propelling means in form of chains, cog wheels or discs arranged on both sides of the baths and subjected to a revolving motion, possibly an eccentric revolving motion. In these prior art developing apparatus which may be considered working according to the clipping principle the film is thus on the one hand dipped into and lifted out of the different baths and, on the other hand, transferred from one bath into the following one. Apparatus of this kind are, however, provided with a complex propelling device and are therefore expensive both in purchase and maintenance.

Developing apparatus are also known in which the film is advanced between a system of rolls which convey the film from one both to a following one. Apparatus of this kind which may be considered operating according to the reeling principle required, however, a certain minimum length of the film so that the latter may be processed at all as well as the film being guided by means of rolls during its dipping into the processing liquid. Apparatus of this kind are therefore also complicated and expensive and can therefore not be used for small plates or short film stumps.

The present invention has for its object to avoid the drawbacks and to provide a simple and cheap apparatus for the development of photographic film, particularly X-ray film as for instance dental film. Said apparatus making it possible for doctors and particularly dentists to arrange for the development of their X-ray films with a minimum of supervision and costs.

The invention is essentially characterized in that the developing appartus is provided with a rotatable rod for propelling the film hanger or hangers, said hangers being arranged so that they can be easily releasably connected to said rod so as to be propelled by the rotation of said rod. The releasable connection of the hanger or hangers is preferably constituted by a coupling allowing the rotation of the hanger or hangers around a point located on or adjacent to the axis of the propelling rod, either around the axis or in a plane through said axis.

3,443,503 Patented May 13, 1969 In order to achieve that the hanger ends opposite to the propelling rod move upward from the processing baths or downward toward said baths and consequently lift the film out of said bath or dip it into it, the hanger or hangers are preferably arranged to be displaced laterally by the rotation of the propelling rod over guiding means as for instance cams which are exerting a torque on the hangers around their journalling axis on the propelling rod.

According to a preferred embodiment of the invention the propelling rod is at least as long as the sum of the widths of the processing tanks and journalled in a plane parallel to the liquid surface of the baths as wellas provided with a spaced-pitch screw-thread in which the coupling of the hangers arranged in a threaded shape registering with the thread of the propelling rod are to be engaged. Said coupling has preferably the shape of a hook which is to be engaged in the screw thread from the underside of the propelling rod, the hanger guiding cams being arranged at such a distance from the propelling rod that the outer ends of the hangers exert a torque on the hanger around the contact point against the corresponding cam so that the hanger coupling is maintained in engagement with the propelling rod by the hanger weight.

According to another embodiment of the invention the propelling rod is arranged perpendicularly to the processing bath liquid levels, the processing baths being arranged essentially along a circular path which is concentric to the propelling rod axis, the hanger or hangers being releasably connectable with the propelling rod so as to be driven by the revolving movement of said propelling rod at the same time as the hangers may rotate in a plane through the propelling rod axis. In this embodiment the hanger guide means are preferably arranged along a path concentric to the revolution axis of the propelling rod.

The tanks for the development bath and the fixing bath and possibly a tank for an inhibitor bath are also preferably arranged in a larger common rinsing water bath maintained at a constant liquid temperature, which may for instance be arranged by providing the tank with a feed pipe supplying temperate water and an overflow in such a way that the processing bath tanks are circumfiown by the rinsing water.

By adequately adapting the width of the tanks, the distance between the tanks as well as the lifting portion of the various cams it is, at a given revolution speed of the propelling rod, possible to achieve that the film will remain immersed in each tank and in the rinsing water bath exactly as long time as is required considering the characteristics of the processed film.

According to a further embodiment of the invention the propelling rod can be provided with a device bringing about that the hanger which has been shifted to the last bath, usually a rinsing bath, is maintained in that position with the film immersed in the bath and its further advancement eventually not occurring until the subsequent hanger is transferred to the end position.

A preferred embodiment of the invention has for its object to provide the possibility of development in daylight in that the developing apparatus is provided with a hood of translucent material, preferably a plastic or acrylic, acrylonitrile, styrene, or polystyrene type or modifications of these materials, said material being deep colored so as to be permeable only to light of a wave length to which the film stock is non-sensitive but which allows a good visibility of the objects underneath the hood. It is preferable to choose such a material and to color it in such a way that the hood absorbs light rays up to a wave length of at least 5500-6500 A.

According to a further embodiment of the invention the hood is also provided with an opening arranged as a light trap allowing to introduce by hand lightproof-packaged film under the hood where it can be manipulated as required. The light trap preferably consists of a curtain constituted by closely spaced strips, strings or chains arranged in one or more layers, in which latter case the strips of the various layers are forming a certain angle in relation to each other. Another possibility is to cover the opening with an elastic cloth of rubber, sponge rubber or the like and to provide said cloth with holes which are normally closed owing to the elasticity of the material and which can be widened so that the operator can introduce his hands inside the hood through said cloth.

A further possibility of arranging a light trap consists in covering the opening in the hood with a tight fitting material provided with cuffs which fit the wrists when the hands are introduced through the opening.

The invention will be described more in detail below, reference being made to the attached drawing, on which FIGURES l, 2 and 3 show a preferred embodiment of the invention, while FIGURES 4 and 5 show another embodiment of said invention.

In the embodiment shown in FIGURE 1 the developing apparatus consists of a tank 9 filled with a rinsing liquid up to a level 9a. The tank end facing the onlooker is closed by a lid and a tank 8 for the developing bath 8a as well as a tank 18 for the fixing bath 18a are immersed in the rinsing liquid. Beyond both these tanks a rinsing bath is formed between the rear end wall of the tank 9 and the container 18, said rinsing bath being constituted by the rinsing liquid in which the tanks 8 and 18 are immersed. Between said tanks a further tank for an inhibitor bath can eventually be arranged, unless also in this case, as shown in FIGURE 3 so as to provide said coupling as an intermediate rinsing bath.

In the embodiment shown the various baths are thus arranged in succession. Hangers 5, 6, 11 are arranged for dipping the film into the various baths and lift them out of said baths, said hangers being provided with clips 2 in which the films 7 can be fastened as shown in FIGURE 2. The hangers are constituted by a yoke part 1 the end of which is provided with a coupling part 3. Seen in side view said coupling has the shape of a hook which, for reasons explained below, is somewhat distorted laterally as shown in FIGURE 3 so as to provide said coupling part with a thread-like shape.

For the propulsion of the hangers along the various baths the tank 9 is, according to the invention, provided with a pr0pelling rod 14 which in the embodiment shown is provided with a high-pitched screw thread in which the coupling part 3 of the various hangers are intended to be engaged from below. The hanger yoke 1 is brought to rest against a cam, for instance 12, 13, and due to the weight of the opposite hanger end and eventually the weight of the film said hanger will rotate in a vertical plane around its contact point against said cam 12, 13 etc. until the coupling part 3 will abut from below against the propelling rod 14 and thus rest in a thread of said rod. The earns 12, 13 etc. which are arranged parallel to the propelling rod are spaced at such a distance from the rod and provided with such a profile that the hangers will dip the film into the various baths only when the hangers are located straight in front of the baths while the hangers will be steeply inclined when located in another position along the propelling rod so as to maintain the film above the tank edges.

The propulsion of the hangers is effected in that the propelling rod 14 which is journalled at both ends in the tank 9 is brought to revolve in one direction in such a way that the hangers engaging the screw thread of the rod with their couplings will glide ahead along the cams 12, 13 etc. The revolving of the propelling rod is preferably achieved by an electric motor 15 driving the 4 rod via a V-belt or the like. The current to the electric motor can be supplied through a cable 16.

The propelling rod 14 end 4 opposite to the onlooker is not provided with a screw thread and its diameter is preferably smaller than that of the thread bottom so that a hanger which has been advanced to the final rinsing bath will remain in horizontal position with the film immersed in the rising bath until for instance the following hanger also leaves the screw thread and pulls the first hanger ahead and possibly up on a cam so that the film is lifted out of the ransing bath. In addition to the guiding earns 12, 13 etc. the developing apparatus according to the invention can also be provided with waveshaped cams 10 arranged along the rinsing tank edge, which cams 10 inpart the hangers an up and down motion which firstly results in a wave-shaped motion of the film in the various baths, secondly activate the various developing processes and thirdly contributes to a certain stirring of the liquid in the baths.

The developing apparatus according to the invention can possibly be provided with a lightproof sealing lid or hood 9b which can be opened.

The apparatus operates as follows.

The device being placed in a darkroom and the developing bath, the fixing bath and the rinsing bath being filled, the lid is opened whereupon the exposed film 7 is fastened to the clips 2 of the hanger 6. The coupling part 3 of the hanger 6 is thereafter engaged from below in the screw thread of the rod 14 in front of the starting cam 12 whereupon the drive motor 15 is started. The lid is thereafter closed and the apparatus is left to achieve the development processing entirely automatically. In the course of this processing the hanger 6 is first propelled to a point in front of the tank 8 the hanger 6 gliding along a recess in the cam 13 so as to be rotated downwards in horizontal position and immerse the film 7 in the liquid 8a. During the further propelling of the hanger 6 along the propelling rod 14 the hanger is brought up on the cam 12 so that the film is lifted over the side edge of the tank 8 to be thereafter immersed in the following bath. The processing continues in this way until the film has been immersed in all baths and the hanger 6 has been pushed off the screw thread so that the coupling part 3 engages the small diameter end 4 of the propelling rod 14. Several hangers carrying film are thereafter propelled in the same way. When followed by other work the developed and rinsed film can thereafter be taken out of the developing apparatus.

Another development of the invention will now be described with reference to FIGURES 4 and 5. It can be seen in FIGURE 4 the tanks 8, 8b, 18 etc. containing the various processing baths have been arranged along a circular path while the propelling rod 14 has been arranged perpendicularly to the levels of the processing liquid and concentrically to said path. The propelling rod 14 is radially provided with journalling means 3a located at the height slightly below the edges of the various tanks, which journalling means can be engaged by correspondingly arranged coupling means 3 on the hangers 6. The journalling means are provided with two guiding surfaces parallel to a radial plane, which guiding surfaces, when the propelling rod 14 is rotating, drive a hanger, the coupling part 3 of which engages the journalling means. The hanger is rotatable in a plane through the axis of the propelling rod 14 around a pivot 3b arranged perpendicularly through both said guiding surfaces. Concentrically to the propelling rod 14 are arranged cams against which the yoke part 1 rests and which achieve that the hangers, like in the previously described embodiment, are imparted an up and down rotation during the revolution of the propelling rod 14. The profile of said guiding earns 12, 13 etc. is arranged in such a way in relation to the position of the various bath tanks along the circular path that the film fastened to the clips 2 of such a hanger will be successively immersed in and lifted out of the various baths like in the previously described embodiment.

Although the invention has been described with reference to one embodiment it may, however, be varied within the scope of the subsequent claims.

What we claim is:

1. Apparatus for intermittently immersing photographic film in a plurality of successive liquid processing baths comprising:

(a) a shaft mounted for rotation about its axis;

(b) means for rotating said shaft;

(c) at least one hanger having means at one end for supporting photographic film;

(d) means for rotatably connecting the other end of said hanger to said shaft whereby said one end of the hanger is moved along the successive liquid processing baths as said shaft is rotated;

(e) a cam engaging surface on said hanger;

(f) a stationary cam surface positions to cooperate with said cam engaging surface for selectively rotating said hanger in opposite directions to selectively cause said photographic film to be immersed into and withdrawn from said liquid processing baths; and

(g) a second cam surface cooperating with said cam engaging surface when the film is immersed in the baths, said second cam surface having a series of short projections to subject the film to up and down motion in said baths to cause a stirring of the bath liquid around the film so as to achieve a uniform processing.

2. Apparatus for intermittently immersing photographic film in a plurality of successive liquid processing baths comprising:

(a) a shaft mounted for rotation about its axis;

(b) means for rotating said shaft;

(c) at least one hanger having means at one end for supporting photography film;

(d) means for rotatably connecting the other end of said hanger to said shaft whereby said one end of the hanger is moved along the successive liquid processing baths as said shaft is rotated;

(e) a cam engaging surface on said hanger;

(f) a stationary cam surface positioned to cooperate with said cam engaging surface for selectively rotating said hanger in opposite directions to selectively cause said photographic film to be immersed into and withdrawn from said liquid processing baths; and

(g) a hood of transparent plastic material, said material being deep-colored so as to be permeable only to light of a wave length to which the film stock is not sensitive but which allows a good visibility of the objects beneath the hood.

3. Apparatus for intermittently immersing photographic film in a plurality of successive liquid processing baths as defined in claim 2 wherein said hood is made of a material absorbing light rays up to a wave length of at least 5500 to 6500 A.

4. Apparatus for intermittently immersing photographic film in a plurality of successive liqcid processing baths comprising:

(a) a shaft mounted for rotation about its axis;

(b) means for rotating said shaft;

(c) at least one hanger having means at one end for supporting photographic film;

((1) means for rotatably connecting the other end of said hanger to said shaft whereby said one end of the hanger is moved along the successive liquid processing baths as said shaft is rotated;

(e) a cam engaging surface on said hanger;

(f) a stationary cam surface positioned to cooperate with said cam engaging surface for selectively rotating said hanger in opposite directions to selectively cause said photographic film to be immersed into and withdrawn from said liquid processing baths; and

(g) wherein said shaft is arranged perpendicularly to the liquid surface in said processing baths, said baths being arranged in a circular path around the axis of said shaft, and said hangers being rotatable in a plane through said shaft by said stationary cam surface.

5. Apparatus for intermittently immersing photo 5 graphic film in a plurality of successive liquid processing baths as defined in claim 4 wherein said stationary cam surface is arranged along a path concentric to the axis of said shaft.

References Cited UNITED STATES PATENTS 2,912,915 11/1959 Hiserman 95-97 X 2,927,521 3/1960 Smith 95-89 X 3,196,772 7/1965 Sickles 9589 2,527,959 10/ 1950 Quinn 9589 NORTON ANSHER, Primary Examiner.

CHARLES E. SMITH, Assistant Examiner. 

